\documentclass{article}
%% compiler avec lualatex
\usepackage[margin=2.5cm]{geometry}
\usepackage{luamesh}
\usepackage{fontspec}
\usepackage{multido}
\pagestyle{empty}


\begin{document}

\multido{\ii=5+1}{3}{%
  \newpage
  \meshAddPointBWinc[
  mode=ext,step=badtriangles,
  colorNew =green!20!red,
  colorBack=red!10,
  colorCircle = blue,
  ]
  {mesh.txt}{\ii}%
  {%
    beginfig(0);
  }%
  {%
    draw (-1,-1)*u--(7.5,-1)*u--(7.5,5)*u--(-1,5)*u--cycle withcolor 0.99white;
    clip currentpicture to (-1,-1)*u--(7.5,-1)*u--(7.5,5)*u--(-1,5)*u--cycle;
    endfig;
  }  \newpage
  \meshAddPointBWinc[
  mode=ext,step=cavity,
  colorNew =green!20!red,
  colorBack=red!10,
  colorCircle = blue,
  ]
  {mesh.txt}{\ii}%
  {%
    beginfig(0);
  }%
  {%
    draw (-1,-1)*u--(7.5,-1)*u--(7.5,5)*u--(-1,5)*u--cycle withcolor 0.99white;
    clip currentpicture to (-1,-1)*u--(7.5,-1)*u--(7.5,5)*u--(-1,5)*u--cycle;
    endfig;
  }  \newpage
  \meshAddPointBWinc[
  mode=ext,step=newtriangles,
  colorNew =green!20!red,
  colorBack=red!10,
  colorCircle = blue,
  ]
  {mesh.txt}{\ii}%
  {%
    beginfig(0);
  }%
  {%
    draw (-1,-1)*u--(7.5,-1)*u--(7.5,5)*u--(-1,5)*u--cycle withcolor 0.99white;
    clip currentpicture to (-1,-1)*u--(7.5,-1)*u--(7.5,5)*u--(-1,5)*u--cycle;
    endfig;
  }
}



\end{document}
